1. Field of the Invention
The present invention relates to an in-furnace temperature measuring method that is suitable in a temperature measurement for a reflow furnace or the like that requires a temperature management.
2. Description of the Related Technology
For example, electronic parts that are soldered onto a printed circuit board by a reflow furnace are being enhanced in performance and densely implemented. For that reason, the diversification of the electronic parts (large-sized, small-sized, etc.) is advanced, and the necessity of the temperature management within the reflow furnace is more and more required. Also, a precision in temperature measurement which is required for the temperature analysis within the reflow furnace has been improved.
Up to now, in the case of measuring the temperature within the reflow furnace, as shown in FIG. 5, a printed circuit board 51, whose given physical values (specific heat, density, heat transfer coefficient, etc.) have been known, or the like is inserted into a reflow furnace 52, and a surface temperature of the printed circuit board 51 is measured at given positions 52a and 52b. 
In addition, an air temperature within the reflow furnace 52 is measured in a state where the printed circuit board 51 is not inserted into the reflow furnace 52. For example, a thermo couple 53 is used in those temperature measurements. In addition numeral 54 shown in FIG. 5 denotes conveying device.
However, in the conventional temperature measuring method, since the temperature measurement operation of plural times is required in order to obtain necessary data, there arises such a problem in that the number of operation steps is increased.
Also, since the printed circuit board 51 or the like used in the temperature measurement is colored with substantially the same color as that of an actual printed circuit board, there arises such a problem in that the measurement results cannot be applied to a printed circuit board that is different in the color and a finishing state from the printing circuit board 51 as they are.
Also, because the surface temperature of the printed circuit board 51 for examination and the air temperature within the reflow 52 are measured, individually, there arises such a problem in that it is difficult to determine the temperature in a state where the electronic parts are mounted on the actual printed circuit board.
In addition, since the surface temperature of the printed circuit board 51 and the air temperature within the reflow furnace 52 are measured, separately, there arises such a problem in that the positional displacement of the measured position occurs, and the reliability of the measured result is lowered.
The above problems occur not only in the reflow furnace, but also in various furnaces that require the temperature management.                [Patent Document 1] JP2004-245732A        [Patent Document 2] JP01-51127A        